Nuclear energy continues to be an important source of energy for the United States and many countries around the world, as nuclear fuel can provide greater amounts of energy over long time periods without many of the problems associated with fossil fuel use, such as greenhouse gas emissions. The inherent risks in using and storing nuclear fuel sources, the need for ensuring safe operation of nuclear reactors, and the risks of nuclear fuel being misused to create weapons continue to drive innovation in developing safe and secure nuclear fuel technologies.